Question: $ { \left[\begin{array}{rrr}{-1} & {0} & {1} \\ {1} & {3} & {1}\end{array}\right]+\left[\begin{array}{rrr}{1} & {-1} & {-2} \\ {2} & {0} & {3}\end{array}\right] = {?} } $
Explanation: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rrr}{-1}+{1} & {0}+{-1} & {1}+{-2} \\ {1}+{2} & {3}+{0} & {1}+{3}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{0} & {-1} & {-1} \\ {3} & {3} & {4}\end{array}\right]}$